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Cross sections for inelastic 2-to-2 meson-meson scattering in hadronic matter
Ting-Ting Wang, Xiao-Ming Xu
Published:   , doi: 10.1088/1674-1137/43/2/024102
Abstract:
With quark-antiquark annihilation and creation in the first Born approximation, we study the reactions: \begin{document}$K \bar {K} \to K \bar {K}^\ast$\end{document} , \begin{document}$K \bar{K} \to K^* \bar{K}$\end{document} , \begin{document}$\pi K \to \pi K^\ast$\end{document} , \begin{document}$\pi K \to \rho K$\end{document} , \begin{document}$\pi \pi \to K \bar{K}^\ast$\end{document} , \begin{document}$\pi \pi \to K^\ast \bar{K}$\end{document} , \begin{document}$\pi \pi \to K^\ast \bar{K}^\ast$\end{document} , \begin{document}$\pi \rho \to K \bar{K}$\end{document} , \begin{document}$\pi \rho \to K^\ast \bar{K}^\ast$\end{document} , \begin{document}$\rho \rho \to K^\ast \bar{K}^\ast$\end{document} , \begin{document}$K \bar{K}^\ast \to \rho \rho$\end{document} , and \begin{document}$K^* \bar{K} \to \rho \rho$\end{document} . Unpolarized cross sections for the reactions are obtained from transition amplitudes that are composed of mesonic quark-antiquark relative-motion wave functions and the transition potential for quark-antiquark annihilation and creation. From a quark-antiquark potential that is equivalent to the transition potential, we prove that the total spin of the two final mesons may not equal the total spin of the two initial mesons. Based on flavor matrix elements, cross sections for some isospin channels of reactions can be obtained from the other isospin channels of reactions. Remarkable temperature dependence of the cross sections is found.
Description of the critical point symmetry in 124Te by IBM-2
Da-Li Zhang, Cheng-Fu Mu
Published:  
Abstract:
Based on the neutron and proton degrees of freedom, the low-lying energy levels, the \begin{document}$ E2 $\end{document} , \begin{document}$ M1 $\end{document} and \begin{document}$ E0 $\end{document} transition strengths of nucleus \begin{document}$ ^{124} $\end{document} Te have been calculated by the neutron-proton interacting boson model. The calculated results are quite consistent with the experimental data. By comparing the key observables of states at the critical point of \begin{document}$ \rm{U}_{\pi \nu}(5) $\end{document} -- \begin{document}$ \rm{O}_{\pi \nu}(6) $\end{document} transition with experimental data and calculated results, we show that the \begin{document}$ ^{124} $\end{document} Te is a possible nucleus at the critical point of the second order phase transition from vibration to unstable rotation and such a critical point contains somewhat triaxial rotation. The 0 \begin{document}$_2^ + $\end{document} state of \begin{document}$ ^{124} $\end{document} Te can be interpreted as the lowest state of the first excited family of intrinsic levels in the critical point symmetry.
Simple Black Holes with Anisotropic Fluid
Inyong Cho, Hyeong-Chan Kim
Published:  
Abstract:
We study a spherically symmetric spacetime made of anisotropic fluid of which radial equation of state is given by \begin{document}$ p_1 = -\rho $\end{document} . This provides analytic solutions and a good opportunity to study the static configuration of black hole plus matter. For a given equation-of-state parameter \begin{document}$ w_2 = p_2/\rho $\end{document} for angular directions, we find exact solutions of the Einstein's equation described by two parameters. We classify the solution into six types based on the behavior of the metric function. Depending on the parameters, the solution can have event and cosmological horizons. Out of these, one type corresponds to a generalization of the Reissiner-Nordström black hole, for which the thermodynamic properties are obtained in simple forms. The solutions are stable under radial perturbations.
A dynamical description of 136Xe + p spallation at 1000 MeV/nucleon
Fan Zhang, Jun Su
Published:   , doi: 10.1088/1674-1137/43/2/024103
Abstract:
This work proposes a dynamical description of the 136Xe + p spallation at 1000 MeV/nucleon with the aim of probing the mechanism which rules the IMFs production. The isospin-dependent quantum molecular dynamics (IQMD) model is applied to describe the dynamical process of the spallation until the hot fragments with excitation energy less than a special value Estop are formed. The statistical code GEMINI is applied to simulate the light-particle evaporation of the hot fragments. It is found that the IMFs production is well described by the model when the Estop = 2 MeV/nucleon is used. But comparison of the mean neutron-to-proton ratios between the data and calculations indicates the value of Estop = 3 MeV/nucleon.
Scalar quintuplet minimal dark matter with Yukawa interactions: perturbative up to Planck scale
Zhu Luo, Chengfeng Cai, Zhaofeng Kang, Zhaohuan Yu, Honghao Zhang
Published:   , doi: 10.1088/1674-1137/43/2/023102
Abstract:
We confront the perturbativity problem in the real scalar quintuplet minimal dark matter model. In the original model, the quintuplet quartic self-coupling inevitably hits a Landau pole at a scale ~1014 GeV, far below the Planck scale. In order to push up this Landau pole scale, we extend the model with a fermionic quintuplet and three fermionic singlets which couple to the scalar quintuplet via Yukawa interactions. Involving such Yukawa interactions at a scale ~1010 GeV not only can keep all couplings perturbative up to the Planck scale, but also can explain the smallness of neutrino masses via the type-I seesaw mechanism. Furthermore, we identify the parameter regions favored by the condition that perturbativity and vacuum stability are both maintained up to the Planck scale.
A model to explain angular distributions of $ {{J /\psi}} $ and $ {{\psi(2S)}} $ decays into $ \Lambda \overline \Lambda $ and $ \Sigma^0 {\overline \Sigma}{}^0 $
M. Alekseev, A. Amoroso, R. Baldini Ferroli, I. Balossino, M. Bertani, D. Bettoni, F. Bianchi, J. Chai, G. Cibinetto, F. Cossio, F. De Mori, M. Destefanis, R. Farinelli, L. Fava, G. Felici, I. Garzia, M. Greco, L. Lavezzi, C. Leng, M. Maggiora, A. Mangoni, S. Marcello, G. Mezzadri, S. Pacetti, P. Patteri, A. Rivetti, M. Da Rocha Rolo, M. Savrié, S. Sosio, S. Spataro, L. Yan
Published:   , doi: 10.1088/1674-1137/43/2/023103
Abstract:
BESIII data show a particular angular distribution for the decay of the \begin{document}$ J/\psi $\end{document} and \begin{document}$ \psi(2S) $\end{document} mesons into the hyperons \begin{document}$ \Lambda \overline \Lambda $\end{document} and \begin{document}$ \Sigma^0 {\overline \Sigma}{}^0 $\end{document} . More in details the angular distribution of the decay \begin{document}$ {{\psi(2S)}} \to {\Sigma^0\overline{\Sigma}{}^0} $\end{document} exhibits an opposite trend with respect to that of the other three channels: \begin{document}$ J/\psi \to \Lambda \overline \Lambda $\end{document} , \begin{document}$ J/\psi \to \Sigma^0 {\overline \Sigma}{}^0 $\end{document} and \begin{document}$ \psi(2S) \to \Lambda \overline \Lambda $\end{document} . We define a model to explain the origin of this phenomenon.
A light scalar in the Minimal Dilaton Model in light of LHC constraints
Lijia Liu, Haoxue Qiao, Kun Wang, Jingya Zhu
Published:   , doi: 10.1088/1674-1137/43/2/024104
Abstract:
Whether an additional light scalar exists is an interesting topic beyond the Standard Model (SM), while nowadays we do not know exactly physics beyond the SM in the low mass region, e.g., the Atlas and CMS collaborations get inconsistent results at around 95 GeV in searching for light resonances in diphoton channel. Considering these, we study a light scalar in the Minimal Dilaton Model (MDM). Under the theoretical and latest experimental constraints, we sort the surviving samples into two scenarios according to the diphoton rate of the light scalar: the large-diphoton scenario (with \begin{document}$\sigma_{\gamma\gamma}/SM\gtrsim0.2$\end{document} ) and the small-diphoton scenario (with \begin{document}$\sigma_{\gamma\gamma}/SM\lesssim0.2$\end{document} ), which are favored by CMS and Atlas results respectively. We compare the two scenarios, check the characteristics in model parameters, scalar couplings, production and decay, and consider further distinguishing them at colliders. Finally, we get the following conclusions for the two scenarios: (i) The formal usually has small Higgs-dilaton mixing angle ( \begin{document}$|\sin\theta_S|\lesssim0.2$\end{document} ) and small dilaton vacuum expectation value (VEV) \begin{document}$f$\end{document} ( \begin{document}$0.5\lesssim\eta\equiv v/f\lesssim1$\end{document} ), and the later usually has large mixing ( \begin{document}$|\sin\theta_S|\gtrsim0.4$\end{document} ) or large VEV ( \begin{document}$\eta\equiv v/f\lesssim0.3$\end{document} ). (ii) The former usually predicts small \begin{document}$s\gamma\gamma$\end{document} coupling ( \begin{document}$|C_{s\gamma\gamma}/SM|\lesssim0.3$\end{document} ) and large \begin{document}$sgg$\end{document} coupling ( \begin{document}$0.6\lesssim|C_{sgg}/SM|\lesssim1.2$\end{document} ), while the later usually predicts small \begin{document}$sgg$\end{document} coupling ( \begin{document}$|C_{sgg}/SM|\lesssim0.5$\end{document} ). (iii) The former can interpret the small diphoton excess by CMS at its central value, when \begin{document}$m_s\simeq95$\end{document} GeV, \begin{document}$\eta\simeq0.6$\end{document} and \begin{document}$|\sin\theta_S|\simeq0$\end{document} . (iv) The former usually predicts a negative correlation between Higgs couplings \begin{document}$|C_{h\gamma\gamma}/SM|$\end{document} and \begin{document}$|C_{hgg}/SM|$\end{document} , while the later usually predicts the two couplings both smaller than 1, or \begin{document}$|C_{h\gamma\gamma}/SM|\lesssim0.9 \lesssim|C_{hgg}/SM|$\end{document} .
The Higgs Signatures at the CEPC CDR Baseline
Hang Zhao, Yong-Feng Zhu, Cheng-Dong Fu, Dan Yu, Man-Qi Ruan
Published:   , doi: 10.1088/1674-1137/43/1/024101
Abstract:
As a Higgs factory, The CEPC (Circular Electron-Positron Collider) project aims at precision measurements of the Higgs boson properties. A baseline detector concept, APODIS (A PFA Oriented Detector for the HIggS factory), has been proposed for the CEPC CDR (Conceptual Design Report) study. We explore the Higgs signatures at this baseline setup with \begin{document}$\nu\bar{\nu}$\end{document} Higgs events. The detector performance of reconstructing the charged particles, the photons, and the jets are quantified with H \begin{document}$\to \mu\mu, \gamma\gamma$\end{document} , and jet final states respectively. The resolutions of reconstructed Higgs boson mass are comparable for the different decay modes with jets in the final states. We also analyze the H \begin{document}$\to$\end{document} WW* and ZZ* decay modes, where a clear separation between different decay cascades is observed.